package 已知半径求面积;

import java.util.Scanner;

public class 已知半径求面积 {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		
		System.out.print("输入半径");
		double r = in.nextDouble();
		
		double area;
		area = r * r * 3.14159;
		
		System.out.println("半径为"+r+"的圆的面积是"+area);
		
		
	}

}
